This invention is directed to an extension for a mortise cylinder allowing use of the mortise cylinder in conjunction with a mortise lock on doors of varying thicknesses.
Mortise locks are widely used as a locks for doors. They are strong, capable of being manufactured to incorporate various features and because the components of the lock are encased within a lock housing they are adaptable to many different types of doors.
A typical mortise lock includes a lock housing, having an appropriate bolt or latch mechanism located therein to which are attached mortise cylinders. The mortise cylinders are manufactured either incorporating a cylinder lock, a thumb turn or as a blank. The various mortise cylinders thread into the body of the mortise lock itself to connect the cylinders to the lock.
Typically a mortise cylinder having a cylinder lock therein will be utilized on the outside of a door requiring a key to gain entrance to the door and either a cylinder lock, a thumb turn or a blank would be utilized on the interior of the door, depending upon the access capabilities desired for exiting from the interior through the door.
If it is desirous to also require the use of a key for exit, a mortise cylinder having a cylindrical lock would also be utilized on the interior of the door, if it was desired to be able to exit from the interior without a key either a thumb turn or a blank would be utilized in the mortise cylinder on the interior side of the door.
Heretofore there has been a certain limitation with respect to utilizing mortise locks on doors. This limitation resides in the length of the mortise cylinders available. Typically, mortise cylinders are available in two sizes: an inch and an eighth length and in an inch and a quarter length. After subtracting from this length an amount sufficient to thread the cylinder into the mortise lock body, the cylinders will only extend from the sides of the body anywhere from about 7/8 of an inch to about one inch. This, thus limits the thickness of the door which can be equipped with presently available mortise cylinders.
While it is conceivable that mortise cylinders could be made in a variety of other lengths to accommodate overly thick doors, since various mortise cylinders must be available incorporating cylinder locks, thumb turns and blanks and must further be available in various finishes some of which would only have very a limited market, manufacturers and suppliers have been hesitant to expand their commitment to supply and maintain an inventory of additional sizes of mortise cylinders. This has inhibited the use of the mortise cylinders in overly thick doors.